Consistent host and organ-occupancy of phyllosphere bacteria in a community of wild herbaceous plant species

Bacteria colonizing the aerial parts of plants (phyllosphere) are linked to the biology of their host. They impact plant-pathogen interactions and may influence plant reproduction. Past studies have shown differences in composition and structure of leaf, flower and host microbiota, but an investigation of the impact of individual taxa on these variations remained to be tested. Such information will help to evaluate disparities and to better understand the biology and evolution of the plant-microbe associations. In the present study, we investigated the community structure, occupancy of host and organ and prevalence of phyllosphere bacteria from three host species collected at the same location. Almost all (98%) of bacterial taxa detected in the phyllosphere were not only shared across leaves and flowers, or different plant species but also had a conserved prevalence across sub-environments of the phyllosphere. We also found non-random associations of the phylogenetic diversity of phyllosphere bacteria. These results suggest that the phyllosphere microbiota is more conserved than previously acknowledged, and dominated by generalist bacteria adapted to environmental heterogeneity through evolutionary conserved traits.